When using soundcloud you see a list of suggested accounts that you can follow. Similarly they keep feeding you with very relevant posts that are most likely to be interesting to you. All this is enabled by soundcloud ranking. This is the way soundcloud analyses the posts made on their platform to know what each and every post is all about. This way soundcloud can tell that your account is about certain topics and can promote your account to people who like such content.. To do this soundcloud has a very well build algorithm that takes into consideration so many things.
What goes on mostly on soundcloud is written posts and other text related content. This text type of content is very easy for the non-human algorithm to understand. In lame language you can say that the algorithm reads the posts and any other text content. This way it can easily understand what the post is all about. For the audio and image posts the algorithm can depend on the text accompanying the post Like the tittle. Therefore make sure that the text is relevant and straight to the point. The algorithm also depends on the peoples interractions with the post.
User engagement with your posts, the more the likes and comments that the viewers make for your posts the more algorithm loves your posts. Your soundcloud account authority, if your account has existed for long and has been making posts about that particular topic and getting many shares, likes and comments, then soundcloud is more likely to favor your account for that topic than a new account that was started yesterday and made a post.